System of vehicle propulsion.



A. GHURGHWARD. SYSTEM OF VEHICLE PROPULSION. APPLICATION rum) MAR. 10, 1910.

32 Patented Mar.31, 1914.

I 1 o 4-1" xi i i 8 l0 WITNESSES! JNYENTUR W R M )Izzxmpza UHURG'HWAHD.

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ALEXANDER CHURCHWARD, OF NEW YORK, N. .Y., ASSIONOR T GENERAL ELECTBIO UNITED STATES PATENT OFFICE.

COMPANY, A CORPORATION OF NEW YORK.

SYSTEM OF VEHICLE PROPULSION.

Specification of Letters Patent. Patented Mar, 31, 1914, Application filed March 10, 1910. Serial No. 548,854.

ator driven by an internal combustion engine. In such installations it is customary to provide the engine with an accelerator,- that is, an auxiliary throttle valve in the air intake of the carburetor, said valve being directly operated by the chauffeur to increase or decrease the supply of explosive mixture to the engine and thus vary the speed of the vehicle by varying the current output of the generator. Such a-system of speed control is disclosed in the-patent to E. J. Berg, No.'801,355, October 10, 1905.

It is ,found' in ractice that there is a tendency to use t e accelerator too frequently, instead ofrelying upon it only when heavy grades are to be overcome. The efiect of using it when starting or when .runnin li htis to cause the engine to race, which is liable to damage it. The present invention aims to prevent this harmful use of the accelerator, and yet secure an efiicient operation of the engine at all times.

To this end, my invention consists in a locking device applied to the accelerator,

and an electromagnetic releasing device which is responsive to a predetermined genvid'e for an automatic openin of the intake when the generator current ecomes insufficient to carry the load,'as' on a heavy grade.

This is accomplished by having an auxiliary throttle in the intake, controlled by. a solenoid having two difi'erential windings, one in series with the" generator and motor,

and the other in shunt-to the'motor armatnre; As a. modification of this. idea,'the

' auxiliary throttle may be actuated by, two

solenoids, one to open and one to close it,

the. solenoids being controlled by a relay incircuit with the generator.

In the accompanying drawing,-Figure 1 is a diagram s owing the electromagnetic device for the accelerator, combined with the automatically-opening auxiliary throttle, and Fig. 2 shows the eccelerator combined with the device for automatically opening and closing an auxiliary throttle by the variations in the generator current.

The generator 1 illustrated is compound wound, and is driven by an internal com} bustion engine whose intake pipe is shown at 2. The generator sup lies current to the motor 3 which propels t e vehicle. In the intake pipe are two fuel controlling throttle valves, 4 5, the former being connected by a rod 6 with an operating pedal 7. A locking lever 8' is fulcrumed at 9 near said pedal, and has a notch 10 adapted to engage with said pedal and prevent it from bein operated. A spring 11 attached to one en of the lever tends to keep these parts engaged in their locked position..- An electromagnet'12 is arranged inproximity to the locking lever, andin aposition to withdraw said lever from engagement with the pedal when. said electromagnet is sufliciently energized. The winding of this magnet is in series with the generator; The engine andenerator run normally at a constant speed? being controlled by a mechanical speed governor, as usual. When the load is light, or the ro'ad'level, the motor rotates at such speed that its counter-electromotive force cuts down the generator current, so

I that the electromagnet 12 is not powerful enough to overcome the spring 11, and the pedal remains locked. But when the vehicle' strikes. a grade or a heavy piece of road, the speed ofthe motor slackens, and the generator current augments sufiiciently to enable the electromagnet to pull down the lever thereby unlocking the pedal. The chauifeur is then at liberty to press down the edal and open the throttle valve 4,

whic will result in speedin up the engine and raising the voltage 0 the generator current, so as to enable the motor to. carry the increased load. In addition to this throttle valve 4, I prefer to provide a sec 0nd throttle valve .5, whose operating rod 13; is arrangedto be actuated by a solenoid having a difierential winding, one coil 14 being in series with the generator-and the other coil 15 in shunt to the motor armature. A dash pot 16 dampens the movements of thtj rod 13. At normal speed, the enerator cu rent .in' the coil 14 is balance by the counter-eleotromotive force of the ,motor in the coil 15. But when the motor slows down on a grade, the coil 14 becomes relatively stronger and pulls the core 17 to the left, thereby o ening the throttle valve 5 and s ceding up t e generator and consequently a so the motor. I prefer to-place the windings 12 and 14: in series with each other, so that both throttle valves may be operated, if desired, to secure a prompter response from the engine.

In the modification shown in Fig. '2, the

auxiliary throttle valve 5 is actuated by the rod 13, which is connected to a movable core I 18 common to two solenoids 19, 20 whose windings are in parallel circuits. derived from the generator circuit. noid circuits'are controlled by an interlock 21, whose relay coil 22 is in shunt to the generator. If desired, the relay may have a differential winding 23 in series with the motor.--

normal .currentthe relayv contacts are; open, but a predetermined increase or decrease in-said current will cause the closing of the circuit of one or the other ofthe solenoids 19, 20, thereby efl'ecting an opening or closingof the throttle valve 5 to speed up or slow down the engine. If the generator is wound with a drooping characteristic, the reverse winding -23 is not needed; but if the characteristic is not drooping, and it is necessary to keep the vea hicle up to; speed on moderate grades, then the reverse winding is used to oflset the effect oftheimain winding of the relay and thus delay the operation of the throttle valve 5. The relay is preferably wound, in any event, to'work with a difierence in potential of about ten volts, so that no delicate adjustments are necessary.

What I claim as new and desire to secure by Letters Patent of the United States, is- 1. A ,gasolene-electric system of vehicle propulsion comprising a generator, a motor supplied with current from said generator, an accelerator throttle valve, a pedal for actuating the same, a locking device for said pedal, and an electromagnet for withdrawing said locking device when the generator current exceeds a predetermined value.

2. A gasolene-electric system of vehicle propulsion comprising a generator, :1 motor supplied with current from said generator,

The two soletwo fuel controlling throttle valves, a pedal for operating one of said throttle valves, a

solenoid for. actuating the otherv of said throttle valves automatically inresponse to variations in the generator current, and an electromagnetic lock for said pedal responsive to a predetermined value of the generator current, whereby said pedal is unlocked andboth of said throttle valves made operable to control the supply of fuel when said generator current exceeds the predetermined value.

3. A gasolene-electric system of vehicle propulsion comprising a generator, a motor supplied with current from saidgenerator, two fuel controlling throttle valves, a pedal for o crating one of said throttle valves, 3.

core or operating the other of said throttle valves, two windings for said core in parallel branch circuits, a relay responsive to changes in the generator current and controlling the flow of current through said windings, and an electromagnetic lock for said pedal responsive to a predetermined value of the generator current, whereby said pedal is unlocked and both of said throttle valves made operable'to control the supply of fuel when saidgenerator currentexceeds the predetermined value.

4. A gasolene-electric system of vehicle propulsion comprising a generator, a motor supplied with current'from said'generator,

two fuel controlling throttle valves, a pedal.

for operating one of said throttle valves and a core for actuating the other, two windings for said .core in parallel branch circuits, one a for opening said valve and the other for closing it, a relay adapted to close 

